I came to think that this was actually also a great opportunity for me to develop my first cumulative functoid. The functoid is then supposed to take the values as input and output the list of values with a comma in between them.

The functoid has been developed and added to my functoid library at http://eebiztalkfunctoids.codeplex.com – free to download. Also another functoid in the library, which has been there for a while is the “CSV Extract” functoid which extracts a specific position from a separated list.